How many program files are automatically opened by the PLC processor when a new project is created?

• A. 1
• B. 2
• C. 3
• D. 4

Answer: (C)

In PLC programming, projects are organized around a main program plus reusable blocks to keep logic modular. When you create a new project, the software typically opens three program files: the main program where the processor starts its cyclic execution, a function block for stateful, reusable logic, and a function for stateless operations that can be called from different places. This three-block setup supports a clean, scalable structure right from the start, which is why three is the standard number opened automatically. While environments can vary and you might see other block types later (like data blocks for stored data), the common default is three program files.